Try-with-resources Feature in Java
In Java, the Try-with-resources statement is a try statement that declares one or more resources in it. A resource is an object that must be closed once your program is done using it. For example, a File resource or a Socket connection resource. The try-with-resources statement ensures that each resource is closed at the end of the statement execution. If we don’t close the resources, it may constitute a resource leak and also the program could exhaust the resources available to it.
You can pass any object as a resource that implements java.lang.AutoCloseable , which includes all objects which implement java.io.Closeable.
By this, now we don’t need to add an extra finally block for just passing the closing statements of the resources. The resources will be closed as soon as the try-catch block is executed.
Syntax: Try-with-resources
try(declare resources here) {
// use resources
catch(FileNotFoundException e) {
// exception handling
}
Exceptions:
When it comes to exceptions, there is a difference in try-catch-finally block and try-with-resources block. If an exception is thrown in both try block and finally block, the method returns the exception thrown in finally block.
For try-with-resources, if an exception is thrown in a try block and in a try-with-resources statement, then the method returns the exception thrown in the try block. The exceptions thrown by try-with-resources are suppressed, i.e. we can say that try-with-resources block throws suppressed exceptions.
Now, let us discuss both the possible scenarios which are demonstrated below as an example as follows:
- Case 1 : Single resource
- Case 2: Multiple resources
Example 1: try-with-resources having a single resource
Java
Output:
Resource are closed and message has been written into the gfgtextfile.txt
Example 2: try-with-resources having multiple resources
Java
Output:
File content copied to another one. Resource are closed and message has been written into the gfgtextfile.txt
